1. Field of Invention
The present invention relates to position indicators in general and in particular to a wheel nut angular position indicator and locking device.
2. Description of Related Art
In the field of automobiles, wheels are commonly secured to a hub or axel of the vehicle by a plurality of wheel nuts or lug nuts. Such wheel nuts are required to be tightened to a specified torque to ensure the wheel is securely retained on the hub. A nut that is tightened too much may risk damaging the nut or the stud extending from the hub, while a nut that is not tightened enough may risk loosening. It is well known that loosened wheel nuts are undesirable due to the possibility of the wheel becoming unstable or loose and possibly losing the wheel.
Previous attempts to indicate whether a wheel nut is tight has been to provide a body locatable around the nut which is has an indicator thereon for indicating to a user when the nut has rotated out of a desired position. Examples of such devices are disclosed in US Patent Application Publication No US2009/0060677 to Adams, published Mar. 5, 2009, the entirety of which is incorporated herein by reference.
Such previous devices however have been difficult and time consuming to install, remove and operate. In particular, such previous designs have an opening for fitting around the wheel nut that has a fixed diameter. Due to this fixed diameter, it has previously been necessary to thoroughly clean the nut prior installation of the device so as to prevent any accumulated dirt and debris from binding the device or impeding the installation. Such fixed diameter devices have also been difficult to install in cold climates where the device may shrink due to the coefficient of thermal expansion of the material used to form the device.
Other difficulties with the previous designs are that the covers have included a fixed cross-section opening through the device. Such fixed opening has made installation more difficult due to the need to accurately align the cover with the wheel nut. Such accurate alignment is difficult in dirty environments, especially when the wheel nut is not adequately cleaned. In addition, previous devices have utilized a differently colored portion that is only visible that wheel nut has been rotated out of a position that it is covered by an adjacent cover. In dirty environments, such color differences are difficult to see when the entire wheel assembly is covered by a layer of dirt, road salt and other debris.